in biology, the process of organisms dispersing into a new environment.


the lateral (outer) bone of the lower arm.

recessive allele

an allele that is not expressed in the phenotype of an individual because it is masked by its dominant alternative.


the random distribution of parental chromosomes resulting in new gene combinations in the offspring.


the process by which a copy of DNA is made.

reproductive advantage

a feature that enables an organism of a breeding population to produce more offspring than other organisms in the same breeding population that lack that particular feature.

reproductive isolation

the inability of two populations of a species to successfully interbreed. The most common reason for reproductive isolation is geographic separation. For example, two groups of one species may be separated from one another by a river.

reproductive success

the contribution of genes to the next generation.


the destruction of bone by osteoclasts.

ribonucleic acid

an important molecule found within the chromosomes that does not carry genetic information but assists in the duplication of DNA; a nucleic acid made up of a series of four bases (adenine, guanine, thymine and uracil), a ribose sugar and a phosphate group.


a disease process that includes the lack of absorption and use of both calcium and phosphorus due to a Vitamin D deficiency causing the incomplete mineralization of the bone.


the abbreviation for ribonucleic acid.


a rugged build; usually characterized as being large bodied and/or having heavily-structured anatomy; the opposite of gracile.